The present invention relates to a method and a device for affecting the ink distribution in vibrating ink systems of printing presses.
Vibrating ink systems are known as shown in EPO 403 861 A1, for example, which have a duct roller circulating in an ink duct, and an ink vibrator roller, which is in operative connection with the duct roller and with a distributing cylinder.
The distributing cylinder is a component of the roller frame of the ink system. The ink vibrator roller periodically swings back and forth between the duct roller and the distributing cylinder and transfers an ink strip from the duct roller to the distributing cylinder. The length of the ink strip is a function of the contact time of the ink vibrator roller with the ink duct and of the speed of rotation of the ink duct.
An effect of the ink distribution in vibrating ink systems of prior art printing presses is known, wherein ink distribution is understood to include the conveying of excess ink back from the rollers of the vibrating ink system into the ink duct at the end of the application, as well as the conveying of additional ink for achieving a new ink profile, constructed on the old ink profile, or the combination of both conveying options.
In connection with a method according to DE-OS 37 07 695, using this effect, with the press rotating, first the ink profile remaining in the ink duct from the previous print application is reduced by closing the ink duct metering elements and, after a defined number of rotations of the ink duct roller, by conveying the amounts of ink zonally present in the ink system as a function of the prior ink profile back to the ink duct, except for a uniformly small, defined ink thickness layer, which is independent of the profile, and which remains on all of the rollers, and thereafter building up the new ink profile corresponding to the new ink application required in the ink system for the subsequent ink application by zonally adjusting the ink metering elements of the ink duct, by setting the length of the ink strip to be transferred into the ink system, and by a defined number of ink system revolutions.
It is a limitation of this prior arts method that affecting the ink distribution in vibrating damping systems is a time-consuming process because of the discontinuous mode of operation of the ink vibrator.
A device has become known from xe2x80x9cPatent Abstracts of Japan, vol. 6, no. 213 (M-167), Oct. 26, 1982xe2x80x9d, and JP 57-120443, which consists of an ink duct roller, an ink-receiving distribution cylinder and an ink vibrator roller that swings back and forth between the ink duct roller and the ink-receiving distributing cylinder. The ink vibrator roller is seated on an end of a lever, and a cam roller, which cooperates with a cam, is arranged on the other end of the lever. The lever is displaced for establishing an operative connection between the ink duck roller, the ink vibrator roller and the ink-receiving distributing cylinder. The operative connection between the ink duct roller, the ink vibrator roller and the ink-receiving distributing cylinder, which then exists, consists in that the ink vibrator roller, which moves back and forth during the running of the press, remains in only a position in which there is a continuous contact between the ink duct roller and the distributing cylinder receiving the ink. Such a position is needed for including the ink vibrator roller and the ink duct roller in a washing operation of the ink system. This prior art publication does not provide any incentive for affecting the ink distribution in vibrating dampening systems.
It is the object of the present invention to provide a method and a device for affecting the ink distribution in printing presses in a short time.
In accordance with the invention, this object is attained by the varying of the speeds of the ink duct roller, the ink distributing roller and the ink vibrator roller. The ink vibrator roller is provided with a support that can be positioned so that the ink vibrator roller can be driven continuously at a maximum speed by the ink duct roller and by the ink distributing roller or cylinder.